To date, headphones and earphones are widely used as devices for listening to voice and music reproduced by sound-reproducing systems. Headphones and earphones are easily carried around together with portable players and therefore can be used even when moving, outdoors, or the like, but since external sound is mostly blocked when they are worn on both ears, the possibility of accidents likely increases during walking, cycling, or the like.
Accordingly, wearable neck speakers are known that are worn not directly on the ears but around the neck of a user, with speakers being disposed in the vicinity of both ears. For example, Patent Literature 1 discloses a neck speaker device configured such that housings each having a speaker are attached to both sides of a neck strap to position, in front of a user, an acoustic image formed by a sound emitted from the sound outlets of the housings. A bass reflex port is formed in the side surface of each housing to improve bass reproduction.